4 years ago I was unhappy with the sound of my car system compared to my home systems. I was using a highly rated head unit and CD changer, but the sound quality was poor. I started to experiment with DACs in the car inspired by Wes Philips of Stereophile. One of my first attempts was a Sony Discman with Toslink out into a Cal Gamma DAC. The sound was fabulous. One of my first tweaks was a Theta TLC which really improved the highs and bass. I then read an artice in Audio Electronics by Gary Galo called "Optimizing the S/PDIF". He discussed the importance of using a true 75 ohm cable with BNC connectors. I then made 75 ohm cables with BNC connectors with parts from The Parts Connection. I modified my DAC and TLC by adding 75 ohm BNC connectors. The sound improvement was as large as adding the TLC. I recently removed the BNC cables and hard wired 75 ohm cable between the "jitter boxes". This was another significant improvement. In the last year I have slowly replaced the Kimber PBJ interconnects with Cardas Cables. Cardas Crosslink is the same price as the PBJ, but much richer with greater harmonics. However, my favorite Cardas is the Neutral Reference. I would appreciate any upgrade ideas any of you have. Thanks